Abstract
Objectives
To evaluate measurement properties of the 5-item Oral Health Impact Profile (OHIP-5) in Thai version, specifically its validity and responsiveness, as well as to compared with the Oral Impacts on Daily Performances (OIDP) and 14-item OHIP (OHIP-14) among patients undergoing conventional prosthodontic treatments. Minimal clinically important difference (MID) values of the treatment were also determined.
Methods
This prospective cohort study was conducted in 133 prosthodontic patients, receiving complete dentures (CCD), removable partial dentures (RPD), or fixed dental prostheses (FDP). Tooth loss conditions were compared based on the number of functional teeth and posterior occluding pairs. Oral health-related quality of life (OHRQoL) outcomes were assessed at baseline (before prosthodontic treatment), and at 3 months and 6 months after treatment, using the OIDP, OHIP-14, and OHIP-5 questionnaires. Differences in OHRQoL scores across tooth loss conditions, and before and after treatment were compared using non-parametric analyses. Convergent validity was examined by Kendall’s Tau-b correlation between OHIP-5, OHIP-14, and OIDP.
Results
Significant differences in OIDP and OHIP scores across tooth loss conditions supported the known-groups validity. The OHIP-5 Thai showed strong correlations with OHIP-14 and OIDP, confirming convergent validity. OHRQoL scores decreased over 6 months after the treatment in all questionnaires, indicating good responsiveness. MID values of the treatment were higher for the CCD and RPD patients, while MID scores for the FDP patients were near zero when assessed using OHIP questionnaires.
Conclusion
The Thai version of OHIP-5 is a valid and responsive instrument for evaluating outcomes of CCD and RPD treatments. However, due to near-zero MID values, it may be less suitable for assessing treatment changes following FDP treatment.
Clinical relevance
The OHIP-5 Thai is a practical and efficient instrument for assessing OHRQoL problems and for evaluating patient outcomes following conventional prosthodontic treatments. Its performance is correlated with longer OHRQoL instruments, making it suitable for both clinical practice and research settings, supporting patient-centered, evidence-based prosthodontic care. The established MID scores offer valuable benchmarks for interpreting clinically meaningful changes. However, its use may be limited in patients with sufficient functional teeth receiving FDP, as it may be unable to capture meaningful changes.
Keywords: Dental prosthesis, Dental treatment, Healthcare, Oral health, Quality of life, Patient-reported outcome
Background
Dental caries and tooth loss are major global oral health issues that significantly impact overall health and quality of life [1, 2]. To restore extensive tooth structure destruction and replace missing teeth, prosthodontic treatments including fixed and removable dental prostheses are frequent treatment options [2]. At present, incorporating patients’ perspective is essential for evaluating impacts of oral diseases and effectiveness of dental treatments [1, 3]. In the evidence-based dentistry, dental patient-reported outcomes (dPROs), assessed through dental patient-reported outcome measures (dPROMs), became a critical part guiding planning and clinical decision-making of a prosthodontic treatment [1, 4].
Oral health-related quality of life (OHRQoL) has been widely used as a quantitative measure in dPROMs. It is defined as an impact of oral health on an individual’s overall quality of life, encompassing physical, psychological, and social dimensions [5]. The use of OHRQoL instruments can provide insights into how dental and oral conditions and treatments influence individual daily lives and well-being. Several OHRQoL questionnaires have been employed to measure prosthodontic treatment outcomes, including the Oral Impacts on Daily Performances (OIDP) [2, 6, 7] and the Oral Health Impact Profile (OHIP), which is available in different forms, such as the 49-item and 14-item versions [8, 9]. In recent years, a shorten version, the OHIP-5, has been proposed to capture four major dimensions: oral function, orofacial appearance, orofacial pain, and psychosocial impacts [10]. The shortest OHIP-5 version significantly reduces evaluation time while maintaining comparable measurement properties to the full-length versions. It has been validated in multiple languages, including German [10], Japanese [11], Swedish [12], English [13], Arabic [14], Persian [15], Spanish [16], and North Macedonian [17].
The OHIP-5 demonstrated robust psychometric properties, establishing it as a practical assessment instrument for evaluating OHRQoL in both prosthodontic and general patient populations [18]. However, prospective clinical studies validating its efficiency in assessing oral health and detecting changes in OHRQoL after prosthodontic treatment remain limited [19–21]. Furthermore, it is essential to identify meaningful change score changes for the OHIP-5 instrument by determining the minimal important difference (MID), also known as the minimal clinically important difference or minimal important change [22]. The MID value represents the smallest score change that patients perceive as important [22]. It is used to detect health status changes in response to interventions or disease progression, and to interpret the clinical significance of OHRQoL changes [23]. Since the MID may vary depending on the type of dental treatment, there is a lack of studies determining and comparing MID values between prosthodontic patients receiving conventional fixed, removable partial, and complete denture treatments.
The objective of this study was to assess measurement properties of the OHIP-5 in Thai version, specifically its validity in comparison with the OHIP-14 and OIDP instruments and its responsiveness among patients undergoing conventional fixed and removable denture treatments. In addition, the MID values were determined across different types of conventional prosthodontic treatment.
Materials and methods
Study design and participants
The present study utilized a prospective observational cohort design, focusing on patients with prosthodontic needs who visited the undergraduate and postgraduate prosthodontic clinics at the Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. The study protocol was approved by the Human Research Ethics Committee of the Faculty of Dentistry (protocol number: HREC-DCU 2022 − 102) and was conducted in accordance with the Declaration of Helsinki Ethical Principles for Medical Research Involving Human Subjects. All participants agreed and signed informed consent prior to study participation. For those who were illiterate, consent was obtained through their legally authorized representatives.
Data was collected from January 2023 to December 2024 by a trained prosthodontist (P.W.). Eligible participants were individuals aged 18 years and older requiring conventional removable and fixed prosthodontic treatments. Fixed prostheses were limited to single- to three-unit restorations in patients with at least 24 functional teeth. Exclusion criteria were patients with neuromuscular or psychological disorders, those unwilling to provide personal information, and individuals undergoing full mouth rehabilitation involving fixed dental prostheses that restore more than four posterior occluding pairs or anterior tooth veneer restorations. Oral examination was performed at baseline, with the OHRQoL outcomes collected at baseline (before the beginning of prosthodontic treatment), and at 3 months and 6 months following the last denture adjustment visit.
Sample size was estimated using G*Power 3.1.9 software [24]. As there is no standardized method for calculating sample size specifically for the MID determination [21, 25, 26], the present study was based on the hypothesis that the OHIP-5 scores would differ before and after prosthodontic treatment, using changes in self-reported oral health as an external anchor for a MID calculation. A previous prospective cohort study in partial denture patient reported a mean (± standard deviation) of OHIP-5 of 5.9 ± 3.5 before and 3.8 ± 3.1 after treatment among patients who reported feeling better in their self-reported oral health [21], yielding an effect size of 0.63. Using the Wilcoxon signed-rank test (matched pairs) with a significance level of 0.05 and power of 0.80, and accounting for a 15% dropout rate as well as stratification by five items of self-reported oral health change, the required sample size was 133 participants. The final participants included 55 patients who received conventional removable complete denture (CCD), 59 who received conventional removable partial denture (RPD), and 19 who received fixed dental prosthesis (FDP) treatments. The higher number of participants receiving removable dentures was due to the greater variability in dental and supporting tissue conditions, denture designs, and prior removable denture experience, which could influence the outcome of interest.
Independent variables
At baseline prior to prosthodontic treatment, tooth loss was examined according to the number of remaining functional teeth and posterior occluding pairs, with participants categorized into groups of < 20 or ≥ 20 functional teeth, and < 4 or ≥ 4 posterior occluding pairs. These cut-points were selected because patients with greater treatment urgency or more severe tooth loss, defined as having < 20 teeth or < 4 occluding pairs, are often associated with poorer masticatory function and OHRQoL [2, 27]. The participants were interviewed for sociodemographic characteristics, including age, sex, and education.
Then, the patients underwent prosthodontic treatment by undergraduate or postgraduate dental students. Three types of treatments with dental prostheses included CCD, RPD, and FDP. In case more than one type of prosthesis was received, the patients were assigned to the prosthesis with a more severe type of tooth replacement; for example, a surveyed crown with a partial denture was categorized as the RPD, whereas when a single denture was made the patient was assigned as CCD.
OHRQoL outcomes
The dPROMs were assessed using three OHRQoL instruments: OIDP, OHIP-14, and OHIP-5 indices. The OIDP evaluates individual perception on difficulties in carrying out eight daily activities classified into three domains; physical (eat, speak, clean), psychological (sleep, maintain emotion, smile), and social (work, social contact) [6, 7]. The participants rated the frequency (from “never” to “everyday”) and severity (from “not affected” to “very severe”) of oral impacts for each activity using a five-level ordinal scale (score 0–5), resulting in item scores ranging from 0 to 25. The score ranges for the physical, psychological, and social domains were 0–75, 0–75, and 0–50, respectively, yielding a total score range of 0 to 200 across all activities. The higher score indicates more frequent and severe problems.
The OHIP-14 was categorized into seven domains: functional limitation (pronouncing, sense of taste), physical pain (pain aching, eating difficulty), psychological discomfort (self-consciousness, feel tense), physical disability (unsatisfied dietary, interrupted meal), psychological disability (difficult to relax or sleep,), social disability (irritable with other people, difficult doing usual job), and handicap (life dissatisfaction, unable to function) [8, 28]. The participants rated severity of the impact based on the five-point ordinal Likert-type scale ranging from no difficulties (score 0) to very frequent difficulties (score 4). The OHIP-14 domain specific and total scores possible ranges are 0–8 and 0–56, respectively.
The OHIP-5 Thai version was created by selecting five unmodified items from the OHIP-14 Thai questionnaire [28], following the structure of the original German and English OHIP-5 versions [10, 13]. The OHIP-14 Thai had previously been translated using a forward-backward method and validated for use in the general Thai population [28]. The OHIP-5 questionnaire comprises four domains of oral function (chewing difficulty, feeling less flavor in food), orofacial pain (painful aching), orofacial appearance (uncomfortable about appearance), and psychosocial impact (difficulty doing usual jobs) [10, 13]. The score ranges for domain-specific items are 0–4 for a single item, 0–8 for two items, and 0–56 for the total score. The higher score indicates more severe impacts of oral/dental problems and difficulties.
Measurement properties of OHIP-5
The measurement properties of the OHIP-5 index were assessed. Convergent validity was evaluated by comparing the OHIP-5 scores with those of the OHIP-14 and OIDP scores, which served as reference standards. Divergent or know-groups validity was determined by analyzing differences in OHRQoL scores across tooth loss conditions. Meanwhile, the responsiveness of OHIP-5, OHIP-14, and OIDP questionnaires was determined by significant score change following prosthodontic treatment.
Self-reported oral health
At baseline, the participants were also asked “How do you feel about your oral health over the last month?” [21]. Their responses were given on a five-level ordinal scale ranging from very poor (1), relatively poor (2), fair (3), good (4), to excellent (5). At the 3- and 6-month follow-ups, the participants rated their perceived changes in overall oral health status following prosthodontic treatment using a five-point global transition scale. The scale ranged from + 2 (much better), + 1 (better), 0 (no change), −1 (worse), to −2 (much worse). An advantage of using this evaluation is that it is less influenced by the individual’s emotional state [29]. The changes in self-reported oral health scores served as an external anchor to determine the MID value. Using an anchor-based method, the MID was calculated as the median of the OHIP change scores of the participants who reported feeling “better” at the 6-month after treatment [21]. The MID values for the OHIP-5, OHIP-14, and OIDP questionnaires were calculated for all participants and by the type of prosthesis received.
Data analysis
The data were analyzed using statistical software programs (IBM SPSS Statistics for Windows, version 28.0; IBM Corp, and StataNow BE, version 18.5; STATA Corp LP). The level of significance was set at 0.05. Descriptive statistics was used to calculate percentages of participants in each group as well as median OHRQoL values and their distributions. Convergent validity of the OHIP-5 Thai was tested by the correlation between summary OHIP-5, OHIP-14, OIDP, and self-reported oral health scores at baseline using the Kendall’s Tau-b test. Significance of the differences in OHRQoL scores across independent variables (sex, marital status, educational level, working status, oral status, and type of prosthesis to be received) was analyzed using Wilcoxon Signed-Rank and Kruskal-Wallis test, followed by Bonferroni adjustments. To assess divergent or known-groups validity, the OHRQoL scores were compared across groups defined by the number of remaining teeth and groups defined by posterior occluding pairs. Responsiveness or sensitivity to change in the OIDP and OHIP scores before and after treatment was evaluated using the Friedman test, adjusted by Bonferroni multiple comparison tests for the groups dependent on the type of prosthetic treatment.
Results
At baseline, 133 participants had an average age of 62.6 ± 10.9 (range: 22–85) years. Baseline median summary scores for the OHIP-5, OHIP-14, and OIDP significantly differed depending on the number of remaining functional teeth (< 20, ≥ 20), posterior occluding pairs (< 20, ≥ 20), and types of prosthesis to be received (Table 1). Prior to prosthodontic treatment, the OHIP-5 score showed significant correlation with OHIP-14, OIDP, and self-report global oral health (Kendall’s Tau b correlation coefficient was 0.767, 0.623, and − 0.197, respectively; p = 0.001).
Table 1.
Baseline characteristics of participants (n = 133)
| Variables | Distribution (%) | Baseline OHRQOL score: median (minimum, maximum) |
||
|---|---|---|---|---|
| OIDP | OHIP-14 | OHIP-5 | ||
| Total | 133 (100.0) | 30 (0, 200) | 13 (0, 56) | 5 (0, 20) |
| Sex | ||||
| Male | 59 (44.4) | 30 (0, 200) | 12 (0, 56) | 5 (0, 20) |
| Female | 74 (55.6) | 30.5 (0, 125) | 13 (0, 44) | 5.5 (0, 16) |
| Marital status | ||||
| Single | 34 (25.6) | 25 (0, 200) | 13 (0, 56) | 6 (0, 20) |
| Married | 82 (61.6) | 30 (0, 129) | 12 (0, 40) | 5 (0, 20) |
| Divorce | 17 (12.8) | 43 (0, 100) | 16 (2, 30) | 8 (0, 13) |
| Education | ||||
| None to primary | 40 (30.1) | 43.5 (0, 102) | 16 (0, 39) | 6.5 (0, 16) |
| Secondary to diploma | 46 (34.6) | 25 (0, 200) | 13 (0, 56) | 5 (0, 20) |
| Bachelor and higher | 47 (35.3) | 30.5 (0, 129) | 8 (0, 40) | 4 (0, 20) |
| Working status | ||||
| Not working | 58 (43.6) | 32 (0, 200) | 15 (0, 56) | 6 (0, 20) |
| Working | 75 (56.4) | 30 (0, 105) | 12 (0, 39) | 5 (0, 14) |
| Oral status | ||||
| Remaining natural teeth: <20 | 78 (58.6) | 36 (0, 200)b | 16.5 (0, 56)b | 7 (0, 20)b |
| ≥20 | 55 (41.4) | 11 (0, 105)a | 7 (0, 35)a | 3 (0, 14)a |
| Posterior occluding pairs: <4 | 85 (63.9) | 33.5 (0, 200)b | 16 (0, 56)b | 6 (0, 20)b |
| ≥4 | 48 (36.1) | 15 (0, 102)a | 7 (0, 37)a | 4 (0, 14)a |
| Type of prosthesis to be received | ||||
| Removable complete denture | 55 (41.3) | 32 (0, 200)b | 17 (0, 56)b | 7 (0, 20)b |
| Removable partial denture | 59 (44.4) | 35 (0, 129)b | 12 (0, 40)b | 5 (0, 20)b |
| Fixed dental prosthesis | 19 (14.4) | 5 (0, 50)a | 1 (0, 17)a | 0 (0, 8)a |
Different superscript letters (a, b) indicate statistically significant different OHRQoL scores between groups determined by Wilcoxon rank-sum or Kruskal–Wallis tests (p < 0.05)
Participant retention rates at three and six months after treatment were 97.0% (n = 121) and 76.7% (n = 102), respectively, indicating the proportion of participants who completed follow-up assessments at each time point. The median OHRQoL scores gradually improved following treatment, as indicated by decreased total scores at both the 3-month and 6-month follow-ups (Fig. 1). Most of the impacts were reported in an oral function domain for the OHIP-5 and in a physical domain for both OHIP-14 and OIDP (Table 2). At 3 months, oral problem persisted among patients with CCD and those wearing RPD, as shown by their OHRQoL scores. By 6 months, most patients with fixed and removable dentures reported OHRQoL scores of zero, indicating the absence of difficulties in performing daily activities.
Fig. 1.
Changes in OHRQoL scores over time as measured by OIDP, OHIP-14, and OHIP-5 indices at baseline, 3 months, and 6 months after prosthodontic treatment. Dots indicate median values, and error bars represent interquartile range. CCD, conventional complete denture; RPD, removable partial denture; FDP, fixed dental prosthesis
Table 2.
Median OHRQoL scores (minimum, maximum) at baseline and after prosthodontic treatments
| OHRQoL scores | Total | Removable complete denture | Removable partial denture | Fixed dental prosthesis | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baseline (n=133) | 3 months (n=121) | 6 months (n=102) | Baseline (n=55) | 3 months (n=51) | 6 months (n=43) | Baseline (n=59) | 3 months (n=54) | 6 months (n=45) | Baseline (n=19) | 3 months (n=16) | 6 months (n=14) | |
| OHIP-5 score | ||||||||||||
| Summary | 5 (0, 20)A | 3 (0, 19)B | 0 (0, 19)C | 7 (0, 20)A | 4 (0, 19)B | 2 (0, 19)B | 5 (0, 20)A | 3 (0, 19)A | 0 (0, 12)B | 0 (0, 8)A | 0 (0, 5)A | 0 (0, 5)A |
| Oral function | 4 (0, 8)A | 1 (0, 8)B | 0 (0, 8)B | 4 (0, 8)A | 2 (0, 8)B | 1 (0, 8)B | 4 (0, 8)A | 1 (0, 8)B | 0 (0, 6)B | 0 (0, 8)A | 0 (0, 2)A | 0 (0, 2)A |
| Orofacial pain | 0 (0, 4)A | 1 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 2 (0, 4)A | 1 (0, 4)A | 0 (0, 4)A | 1 (0, 4)A | 0 (0, 4)A | 0 (0, 2)A | 0 (0, 2)A | 0 (0, 2)A |
| Orofacial appearance | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)A | 0 (0, 4)B | 0 (0, 4)A | 0 (0, 1)A | 0 (0, 1)A |
| Psychosocial impact | 0 (0, 4)A | 0 (0, 4)B | 0 (0, 4)B | 0 (0, 4)A | 0 (0, 4)B | 0 (0, 4)B | 0 (0, 4)A | 0 (0, 3)B | 0 (0, 3)B | 0 (0, 3)A | 0 (0, 1)A | 0 (0, 1)A |
| OHIP-14 score | ||||||||||||
| Summary | 13 (0, 56)A | 7 (0, 54)B | 1 (0, 55)C | 17 (0, 56)A | 10 (0, 54)B | 4 (0, 55)B | 12 (0, 40)A | 7 (0, 45)A | 0 (0, 22)B | 1 (0, 17)A | 0 (0, 11)A | 0 (0, 11)A |
| Functional limitation | 0 (0, 8)A | 0 (0, 8)AB | 0 (0, 8)B | 0 (1, 8)A | 0 (0, 8)A | 0 (0, 8)B | 0 (0, 8)A | 0 (0, 7)A | 0 (0, 3)B | 0 (0, 4)A | 0 (0, 1)A | 0 (0, 1)A |
| Physical pain | 4 (0, 8)A | 2 (0, 8)A | 0 (0, 8)B | 4 (0, 8)A | 4 (0, 8)AB | 2 (0, 8)B | 4 (0, 8)A | 2 (0, 8)A | 0 (0, 8)B | 0 (0, 6)A | 0 (0, 4)A | 0 (0, 4)A |
| Psychological discomfort | 0 (0, 8)A | 0 (0, 8)AB | 0 (0, 6)B | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 7)AB | 0 (0, 6)B | 0 (0, 7)A | 0 (0, 3)A | 0 (0, 3)A |
| Physical disability | 5 (0, 8)A | 2 (0, 8)B | 0 (0, 8)C | 7 (0, 8)A | 4 (0, 8)B | 1 (0, 8)C | 5 (0, 8)A | 2 (0, 8)B | 0 (0, 7)B | 0 (0, 6)A | 0 (0, 3)A | 0 (0, 3)A |
| Psychological disability | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 5)A | 0 (0, 4)A | 0 (0, 3)B | 0 (0, 3)A | 0 (0, 1)A | 0 (0, 1)A |
| Social disability | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)B | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)B | 0 (0, 6)A | 0 (0, 5)A | 0 (0, 3)B | 0 (0, 2)A | 0 (0, 0)A | 0 (0, 0)A |
| Handicap | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)B | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 8)A | 0 (0, 7)A | 0 (0, 7)A | 0 (0, 2)B | 0 (0, 7)A | 0 (0, 1)A | 0 (0, 1)A |
| OIDP score | ||||||||||||
| Summary | 30 (0, 200)A | 15 (0,148)B | 0 (0,133)C | 32 (0,200)A | 20 (0, 148)A | 9 (0, 133)B | 35 (0, 129)A | 20 (0, 130)B | 0 (0, 130)C | 5 (0, 50)A | 0 (0, 26)A | 0 (0, 26)A |
| Physical | 15 (0, 75)A | 8 (0, 50)B | 0 (0, 50)C | 20 (0, 75)A | 11 (0, 50)B | 4.5 (0,50)B | 15 (0, 60)A | 8 (0, 45)A | 0 (0, 40)B | 0 (0, 35)A | 0 (0, 6)A | 0 (0, 6)A |
| Psychological | 5 (0, 75)A | 0 (0, 58)AB | 0 (0, 52)B | 8 (0, 75)A | 0 (0, 58)AB | 0 (0, 52)B | 6 (0, 55)A | 0 (0, 50)AB | 0 (0, 50)B | 0 (0, 20)A | 0 (0, 16)A | 0 (0, 16)A |
| Social | 8 (0, 50)A | 0 (0, 40)B | 0 (0, 40)C | 10 (0, 50)A | 0 (0, 40)AB | 0 (0, 31)B | 10 (0, 45)A | 0 (0, 40)AB | 0 (0, 40)B | 0 (0, 15)A | 0 (0, 5)A | 0 (0, 5)A |
Different superscript capital letters (A, B, C) indicate significant different OHRQoL scores between time points of each overall and domain-specific oral impacts determined by Friedman and post-hoc comparison test (p < 0.05)
Median (interquartile range) changes in OHRQoL scores were presented by global transition categories across prosthesis types (Table 3). The MID referred to the median change in OHRQoL scores among patients who reported feeling “better” (+ 1 score) in their self-reported oral health status at six-month follow-up (n = 64). The median MID (interquartile range, IQR) values were 3 (6) points for OHIP-5, 8.5 (17) points for OHIP-14, and 20 (47) points for OIDP. The MID values varied by types of dental prosthesis, with higher values observed in the CCD and RPD patients compared to FDP. Notably, the MID for FDP treatment was zero when assessed using both OHIP-5 and OHIP-14 questionnaires to detect treatment changes.
Table 3.
Median (interquartile range) changes in OHRQoL scores by global transition categories across prosthesis types, with minimal important difference (MID) values in bold within the “better” category row
| Global transition category (score) | All patients (n = 102) | CCD (n = 43) | RPD (n = 45) | FPD (n = 14) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n (%) | OIDP | OHIP-14 | OHIP-5 | n (%) | OIDP | OHIP-14 | OHIP-5 | n (%) | OIDP | OHIP-14 | OHIP-5 | n (%) | OIDP | OHIP-14 | OHIP-5 | |
| Much better (+ 2) | 5 (4.9) | 50 (22) | 18 (7) | 5 (4) | 3 (7.0) | 55 (2) | 18 (16) | 8 (7) | 2 (4.5) | 33 (26) | 15 (8) | 4.5 (1) | 0 (0.0) | -------- N/A -------- | ||
| Better (+ 1) | 64 (62.7) | 20 (47) | 8.5 (17) | 3 (6) | 28 (65.1) | 22.5 (44) | 12 (14) | 4 (7) | 28 (62.2) | 27 (51) | 8.5 (19) | 3 (8.5) | 8 (57.1) | 1.5 (5) | 0 (3) | 0 (1) |
| No change (0) | 28 (27.5) | 16 (36) | 5 (14) | 1 (6) | 8 (18.6) | 18 (41) | 10 (20) | 3 (8) | 14 (31.1) | 20 (44) | 6.5 (13) | 2 (6.5) | 6 (42.9) | 0 (1.5) | 0 (1) | 0 (0) |
| Worse (−1) | 3 (2.9) | 61 (156) | 16 (62) | 7 (21) | 3 (7.0) | 61 (156) | 16 (62) | 7 (21) | 0 (0.0) | -------- N/A -------- | 0 (0.0) | -------- N/A -------- | ||||
| Much worse (−2) | 2 (2.0) | −32.5 (55) | −13.5 (1) | −4.5 (1) | 1 (2.3) | −60 (0) | −14 (0) | −5 (0) | 1 (2.2) | −5 (0) | −13 (0) | −4 (0) | 0 (0.0) | -------- N/A -------- | ||
CCD Conventional complete denture, RPD Removable partial denture, FDP Fixed dental prosthesis
Discussion
To date, the present study was the first to assess properties of the Thai version of the OHIP-5 questionnaire and to determine the MID values in different types of prosthodontic treatment. The findings indicated that the OHIP-5 shows both known-groups validity, by effectively categorizing the severity of tooth loss, and convergent validity, by aligning with patient-reported problems through the OHIP-14, OIDP, and self-reported global oral health measures. Additionally, the OHIP-5 showed responsiveness to changes following prosthodontic treatment. The MIDs varied depending on the type of prosthodontic treatment, with higher values observed for CCD and RPD compared to FDP. The MIDs identified in this study provide valuable references for assessing the OHRQoL in prosthodontic patients after receiving CCD, RPD, and FDP.
At baseline, the OHIP-5 scores showed significant correlations with the OHIP-14, OIDP, and self-reported oral health, indicating satisfactory convergent validity of the OHIP-5 with other dPROMs, supporting the known-groups validity of the questionnaire. Greater tooth loss severity, reflected by a higher number of tooth replacements, fewer than 20 functional teeth, or fewer than 4 posterior occluding pairs, was associated with higher score of the OHIP-5 Thai questionnaire. After the treatment, the OHIP-5 Thai scores significantly decreased indicating OHRQoL improvement, supporting the responsiveness of the shortest OHIP version consisting of only five items. Based on the present findings, patients receiving removable denture treatment showed a greater reduction in OHRQoL scores at 6 months compared to 3 months, whereas patients with FPDs exhibited similar scores at both follow-up periods. This may be explained by the initial adaptation period to the new denture during the first 3 months, when oral problems still existed. As patients gradually became familiar with the prosthesis, their adaptation ability improved, resulting in enhanced OHRQoL outcomes by the 6-month follow-up. While a previous clinical study reported a denture adaptation period of only one month following CCD treatment [30], our findings indicated a longer adaptation period of up to six months for both RPD and CCD. This was consistent with another study involving FPD, RPD, and CCD, which reported that denture adaptation may require 6 to 12 months [31].
The findings regarding psychometric properties (convergent and known-group validity) of the OHIP-5 Thai are consistent with previous clinical studies related to the OHIP-5 questionnaire in other dental patients [11, 14–17], dental students [17], and general population [13, 15, 17]. Convergent validity of the OHIP-5 in other languages have been reported in different studies through its association with self-reported global oral health [11–15, 17], self-report denture quality [11], and other OHRQoL measures involving OHIP-14, OHIP-49, and the general oral health assessment index (GOHAI) [12, 16]. In this study, the OHIP-5 showed strong correlations with the OHIP-14 (r = 0.767) and OIDP (r = 0.623) but a weak correlation with self-reported oral health (r = −0.197). Previous studies reported higher correlations, such as the Swedish version with OHIP-14 (r = 0.92) and self-reported global oral health (r = 0.41) [12], the Japanese version with OHIP-14 (r = 0.92) and self-reported denture quality (r = 0.64) [11], and the English version with self-reported oral health (r = 0.46) [13]. These differences may reflect variations in study populations and the types of oral health problems reported. Notably, self-reported oral health showed a weaker correlation, likely because it reflects a general perception of overall oral health without capturing specific physical, psychological, or social dimensions addressed by multidimensional OHRQoL measures.
The known-groups validity in other studies of the OHIP-5 questionnaire was supported by higher OHIP-5 scores in individuals with fewer natural teeth [13–15, 17], missing anterior teeth [14], tooth loss without wearing dentures [13, 17], periodontal problems [14], and temporomandibular disorders [10]. Consistent with the present study, the North Macedonian version of the OHIP-5 showed that patients wearing RPD reported higher scores than those with adequate functional dentition or wearing FDP [17]. In terms of responsiveness, studies utilizing the OHIP-5 in various languages demonstrated significant score reductions following dental treatments, including gingivectomy [14], fixed and removable prosthodontics [11, 14, 20, 21], and temporomandibular disorder management [10], confirming the responsiveness of the OHIP-5. These findings support the effectiveness of the OHIP-5 questionnaire in both identifying oral health problems and evaluating dental treatment outcomes.
The MID score for the OHIP-5 in this study was considered dependent on the type of prosthodontic treatment, with higher MID values observed for CCD and RPD compared to FDP. Overall, the MID was 3 points for OHIP-5, 8.5 points for OHIP-14, and 20 points for OIDP summary scores. A previous prospective cohort study in RPD patients reported lower MIDs of 3 points for the OHIP-14 and 2 points for the OHIP-5 [21], possibly due to fewer missing teeth and less extensive tooth replacement. As indicated by higher baseline OHIP-5 score for patients who needed CCDs and RPDs compared to those who needed FPDs, the present study suggests that MID is also influenced by baseline values recorded before prosthodontic treatment. Participants with more severe conditions and higher baseline scores may require greater changes in MID scores to reflect a minimal important change [20]. Furthermore, more clinically impaired oral conditions, such as a higher number of missing teeth, are likely to result in more noticeable improvements following prosthodontic treatment [32].
Based on the present findings, the calculated MID values for both the OHIP-5 and OHIP-14 in patients receiving FPDs were zero, which is likely too small to reflect clinically meaningful changes. This could be attributed to relatively good baseline oral health among these patients, who typically had adequate functional teeth and occluding pairs. Most patients required FPDs due to localized issues such as tooth structure loss or post-endodontic restoration, conditions that may not significantly impact perceived oral health as measured by the OHIP instruments. In contrast, the OIDP yielded a small but meaning median MID of 1.5 in the FPD group. This may be because the OIDP includes an item related to cleaning difficulties, a concern frequently reported by FPD patients but not captured in the OHIP questionnaires. These findings highlight the importance of selecting OHRQoL instruments tailored to specific populations to effectively detect clinically meaningful changes.
In the present study, the oral impacts and problems reported by the patients with prosthodontic treatment needs were commonly related to physical domains in the OHIP-14 Thai and oral function in the OHIP-5 Thai. Following denture delivery, oral health problems gradually decreased after 3 and 6 months post-delivery in removable denture treatment, while in FPD, the problem almost disappeared after the first 3 months and did not change significantly at the 6 months follow-up. In patients receiving RPDs and CCDs, some oral health problems persisted during 3 months after prosthesis delivery, sometimes comparable to pre-treatment levels. During the first 3 months, patients frequently reported pain and discomfort due to difficulties before the complete adjustment of their new dentures. This was in accordance with other cohorts receiving conventional removable denture treatment at the 1-month follow-up when pain predominantly remained [32]. Therefore, consistent follow-up during the first 6 months post-treatment is essential to enhance long-term treatment success for removable dental prostheses.
The present findings highlight the OHIP-5 as the good instrument for assessing dPRO, demonstrating both satisfactory validity and responsiveness evaluating outcomes of different conventional prosthodontic treatments. The MID values established in this study may serve as useful references for clinical practice and research settings involving both patients receiving FDP and removable dentures. However, the obtained values should be interpreted with caution because they may be influenced by methodological differences and individual patient characteristics. It is important to note that the OHIP-14 and OHIP-5 indices may have limited sensitivity in detecting outcomes following a single- to three-unit FDP, as no significant change in MID scores was observed in this group. For small-unit FPDs, professional assessment of prosthesis quality using standardized clinical and radiographic criteria is recommended [33].
Some limitations should be noted in this study. The participants were independent prosthodontic patients without the need for assistance, which may limit the generalizability of the identified MID values to broader populations, including individuals with other oral diseases or those undergoing different types of dental treatments. As this study was conducted exclusively on Thai patients within a single cultural and healthcare context, the findings, including the MID values, may not be directly applicable to populations in other countries where cultural and healthcare system differences may influence how patients perceive and report OHRQoL [21], potentially leading to variations in MID values. The single-center design and reliance on self-reported measures may introduce response bias. Test-retest reliability was not assessed, as most participants began treatment immediately after the baseline assessment. Moreover, the sample size in this study was calculated based solely on the statistical assumption for assessing responsiveness, using an effect size derived from a single population of patients receiving RPD treatment with a non-parametric distribution [21]. However, the required sample size may have been larger if it had been determined based on convergent and known-groups validity analyses. These analyses involve evaluating associations with other OHRQoL instruments and detecting differences between known groups, which may require larger sample sizes to achieve adequate statistical power and assume normality of data distribution.
Future studies should consider multicenter designs and include objective clinical measures, such as masticatory performances, to enhance the validity of the findings. Further research is needed to establish disease-specific and treatment-specific MID values in diverse populations, including younger or older patients who require assistance, and those receiving treatments such as for temporomandibular disorders or endodontic treatment. Longitudinal studies with larger, more heterogeneous participants and randomized controlled trials are recommended to confirm the generalizability and clinical utility of the OHIP-5, particularly in fields such as implant prosthodontics and geriatric dentistry.
Conclusion
This study demonstrates the good properties of the OHIP-5 Thai, including known-groups validity, convergent validity, and responsiveness which was confirmed by decrease of scores after conventional prosthodontic treatment followed by a 6-month period. However, due to near-zero MID values in FPD patients, the OHIP-5 may be less appropriate for assessing treatment-related changes in patients with sufficient functional teeth receiving fixed dental prostheses.
Acknowledgements
None.
Authors’ contributions
N.L. was responsible for conceptualization, methodology, validation, resources, funding acquisition, project administration, supervision, software, formal analysis, visualization, writing–original draft, writing–review & editing. P.W. was responsible for conceptualization, methodology, investigation, validation, data curation, writing–review & editing. All authors reviewed the manuscript.
Funding
Funded by the Ratchadaphiseksomphot Fund, Chulalongkorn University, Bangkok, Thailand [Grant number RCU_68_004_3200_001].
Data availability
The data generated during the current study is available upon request to the corresponding authors.
Declarations
Ethics approval and consent to participate
The study had been performed in accordance with the Declaration of Helsinki and was approved by the Human Research Ethics Committee of the Faculty of Dentistry, Chulalongkorn University (code no. HREC-DCU 2022-102). All participants agreed and signed informed consent prior to study participation. For those who were illiterate, consent was obtained through their legally authorized representatives.
Consent for publication
Not applicable.
Competing interests
The authors declare no potential conflict of interest relating to this study.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Reissmann DR. Dental patient-reported outcome measures are essential for evidence-based prosthetic dentistry. J Evid Based Dent Pract. 2019;19(1):1–6. 10.1016/j.jebdp.2019.01.003. [DOI] [PubMed] [Google Scholar]
- 2.Techapiroontong S, Limpuangthip N, Tumrasvin W, Sirotamarat J. The impact of poor dental status and removable dental prosthesis quality on body composition, masticatory performance and oral health-related quality of life: a cross-sectional study in older adults. BMC Oral Health. 2022;22(1):147. 10.1186/s12903-022-02103-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Reissmann DR. Methodological considerations when measuring oral health–related quality of life. J Oral Rehabil. 2021;48(3):233–45. 10.1111/joor.12983. [DOI] [PubMed] [Google Scholar]
- 4.Limpuangthip N, Phuckdeedindan M, Techapiroontong S. Clinician evaluation of removable complete denture quality: A systematic review of the criteria and their measurement properties. J Prosthet Dent. 2025;133(1):96–107. 10.1016/j.prosdent.2023.01.008. [DOI] [PubMed] [Google Scholar]
- 5.Glick M, Williams DM, Kleinman DV, Vujicic M, Watt RG, Weyant RJ. A new definition for oral health developed by the FDI world dental federation opens the door to a universal definition of oral health. J Am Dent Assoc. 2016;147(12):915–7. 10.1016/j.adaj.2016.10.001. [DOI] [PubMed] [Google Scholar]
- 6.Adulyanon S, Vourapukjaru J, Sheiham A. Oral impacts affecting daily performance in a low dental disease Thai population. Community Dent Oral Epidemiol. 1996;24(6):385–9. 10.1111/j.1600-0528.1996.tb00884.x. [DOI] [PubMed] [Google Scholar]
- 7.Srisilapanan P, Sheiham A. The prevalence of dental impacts on daily performances in older people in Northern Thailand. Gerodontology. 2001;18(2):102–8. 10.1111/j.1741-2358.2001.00102.x. [DOI] [PubMed] [Google Scholar]
- 8.Slade GD. Derivation and validation of a short-form oral health impact profile. Community Dent Oral Epidemiol. 1997;25(4):284–90. 10.1111/j.1600-0528.1997.tb00941.x. [DOI] [PubMed] [Google Scholar]
- 9.Locker D. Measuring oral health: a conceptual framework. Community Dent Health. 1988;5(1):3–18. [PubMed] [Google Scholar]
- 10.John MT, Miglioretti DL, LeResche L, Koepsell TD, Hujoel P, Micheelis W. German short forms of the oral health impact profile. Community Dent Oral Epidemiol. 2006;34(4):277–88. 10.1111/j.1600-0528.2006.00279.x. [DOI] [PubMed] [Google Scholar]
- 11.Baba K, Inukai M, John MT. Feasibility of oral health-related quality of life assessment in prosthodontic patients using abbreviated oral health impact profile questionnaires. J Oral Rehabil. 2008;35(3):224–8. 10.1111/j.1365-2842.2007.01761.x. [DOI] [PubMed] [Google Scholar]
- 12.Larsson P, John MT, Hakeberg M, Nilner K, List T. General population norms of the Swedish short forms of oral health impact profile. J Oral Rehabil. 2014;41(4):275–81. 10.1111/joor.12137. [DOI] [PubMed] [Google Scholar]
- 13.Naik A, John MT, Kohli N, Self K, Flynn P. Validation of the English-language version of 5-item oral health impact profile. J Prosthodont Res. 2016;60(2):85–91. 10.1016/j.jpor.2015.12.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Alhajj MN, Halboub E, Khalifa N, Amran AG, Reissmann DR, Abdullah AG, Assad M, Al-Basmi AA, Al-Ghabri FA. Translation and validation of the Arabic version of the 5-item oral health impact profile: OHIP5-Ar. Health Qual Life Outcomes. 2018;16(1):218. 10.1186/s12955-018-1046-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Nazeri A, Nakhaee N, Navabi N. Validation of an ultrashort Persian version of oral health impact profile (OHIP-5) questionnaire. Pesquisa Brasileira em Odontopediatria e Clínica Integrada. 2020;20(10.1590/pboci.2020.001.
- 16.Simancas-Pallares M, John MT, Enstad C, Lenton P. The Spanish Language 5-Item oral health impact profile. Int Dent J. 2020;70(2):127–35. 10.1111/idj.12534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Elenčevski S, Čelebić A, Popovac A, Apostolska S, Nikolovska J. Stančić I. Psychometric validation of the Macedonian-language version of the ultrashort five-item oral health impact profile in the North Macedonian population (OHIP5-MAC). Medicina. 2025;61(4):655. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.John MT, Omara M, Su N, List T, Sekulic S, Häggman-Henrikson B, et al. Recommendations for use and scoring of oral health impact profile versions. J Evid Based Dent Pract. 2022;22(1):101619. 10.1016/j.jebdp.2021.101619. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.John MT. Standardization of dental patient-reported outcomes measurement using OHIP-5 - Validation of recommendations for use and scoring of oral health impact profile versions. J Evid Based Dent Pract. 2022;22(1s):101645. 10.1016/j.jebdp.2021.101645. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Myint Oo KZ, Fueki K, Inamochi Y, Yoshida-Kohno E, Hayashi Y, Wakabayashi N. Pre-treatment impairment of oral health-related quality of life is associated with variations in minimal clinically important differences among patients with removable partial denture treatment. J Oral Rehabil. 2020;47(7):902–9. 10.1111/joor.12980. [DOI] [PubMed] [Google Scholar]
- 21.Myint Oo KZ, Fueki K, Yoshida-Kohno E, Hayashi Y, Inamochi Y, Wakabayashi N. Minimal clinically important differences of oral health-related quality of life after removable partial denture treatments. J Dent. 2020;92(103246). 10.1016/j.jdent.2019.103246. [DOI] [PubMed]
- 22.de Vet HCW, Mokkink LB, Terwee CB. Minimal important difference. In: Encyclopedia of quality of life and well-being research. edn. Edited by Michalos AC. Dordrecht: Springer Netherlands; 2014: 4073–4074.
- 23.Masood M, Masood Y, Saub R, Newton JT. Need of minimal important difference for oral health-related quality of life measures. J Public Health Dent. 2014;74(1):13–20. 10.1111/j.1752-7325.2012.00374.x. [DOI] [PubMed] [Google Scholar]
- 24.Kang H. Sample size determination and power analysis using the G*Power software. J Educ Eval Health Prof. 2021;18(17). 10.3352/jeehp.2021.18.17. [DOI] [PMC free article] [PubMed]
- 25.Chuang-Stein C, Kirby S, Hirsch I, Atkinson G. The role of the minimum clinically important difference and its impact on designing a trial. Pharm Stat. 2011;10(3):250–6. 10.1002/pst.459. [DOI] [PubMed] [Google Scholar]
- 26.Beaton DE, Hogg-Johnson S, Bombardier C. Evaluating changes in health status: reliability and responsiveness of five generic health status measures in workers with musculoskeletal disorders. J Clin Epidemiol. 1997;50(1):79–93. 10.1016/s0895-4356(96)00296-x. [DOI] [PubMed] [Google Scholar]
- 27.Tan H, Peres K, G,Peres MA. Retention of teeth and oral health-related quality of life. J Dent Res. 2016;95(12):1350–7. 10.1177/0022034516657992. [DOI] [PubMed] [Google Scholar]
- 28.Suksudej S. (2010). The Thai social capital as a social determinant of oral health. University of Adelaide. PhD Thesis.
- 29.Fitzpatrick R, Ziebland S, Jenkinson C, Mowat A, Mowat A. A comparison of the sensitivity to change of several health status instruments in rheumatoid arthritis. J Rheumatol. 1993;20(3):429–36. [PubMed] [Google Scholar]
- 30.Topić J, Poljak-Guberina R, Persic-Kirsic S, Kovacic I, Petricevic N, Popovac A, Čelebić A. Adaptation to new dentures and 5 years of clinical use: A comparison between complete denture and Mini-implant mandibular overdenture patients based on oral Health-Related quality of life (OHRQoL) and orofacial esthetics. Acta Stomatol Croat. 2022;56(2):132–42. 10.15644/asc56/2/4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.John MT, Slade GD, Szentpétery A,Setz JM. Oral health-related quality of life in patients treated with fixed, removable, and complete dentures 1 month and 6 to 12 months after treatment. Int J Prosthodont. 2004;17(5):503–11. [PubMed] [Google Scholar]
- 32.Montero J, Castillo-Oyagüe R, Lynch CD, Albaladejo A. Castaño A. Self-perceived changes in oral health-related quality of life after receiving different types of conventional prosthetic treatments: a cohort follow-up study. J Dent. 2013;41(6):493–503. 10.1016/j.jdent.2013.01.006. [DOI] [PubMed] [Google Scholar]
- 33.Al Refai R, Saker S. Clinical and radiographic assessment of reasons for replacement of metal- ceramic fixed dental prostheses in patients referring to dental school. J Clin Exp Dent. 2018;10(1):e75–80. 10.4317/jced.53850. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data generated during the current study is available upon request to the corresponding authors.